6 Simple Machines

Wheel and Axle

The wheel and axle is one simple machine and not two.

Examples of the wheel and axle are:
      screwdrivers, the windlass, gears, doorknobs,
      winches, spinning wheels, etc

The wheel and axle is a simple machine consisting of two circular objects with different diameters, attached at their centers and working together

In a way, this can be thought of a second class lever, in which the effort is applied to the wheel's circumference, the load is affixed to the axle and the fulcrum is the center of the axle.

The mechanical advantage is the wheel's radius divided by the axle's radius.

mechanical advantage = wheel's radius ÷ axle's radius

And just just like a second class lever, the mechanical advantage is always greater than one.

When in use, the input force can be applied to the wheel:
    screwdriver; doorknob

or applied to the axle:
    ferris wheel; bicycle

A water well with a hand crank that is used to lower and raise a bucket is an excellent example of a wheel and axle (and also a second class lever).

The crank would be considered the "wheel" and the wooden cylinder is the axle.

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